Perforating device



Mai'cbflT, 1942. 1 c. MILLER PERFORATING DEVICE Filed Feb. e, lss

IIIIFIIIIIIII Patente ar l?, i942 PERFORATING DEVICE Leonidas E. Miller, Dallas,

Tex., assignor to American Oil rlool Company, Dallas, Tex., a

corporation oi Texas Application February 6, 1939, Serial No. 254,7419u (Cl. 16d-0.5)

1Q Claims.

This invention relates to new and useful improvements in perforating devices.

As is well known, it has become the practice in the petroleum lndustry to lower'a plurality of explosive charges into a well bore and to re said charges in a predetermined order and at various elevations, whereby the force of the charges is directed radially outwardly of the bore. Such firing of explosive charges may be for the purpose of perforating the well casing, if such casing is in the well, or it may be for the purpose of obtaining cores or samples of the formations at various elevations in the bore. Irrespective of the purpose-for which the charges are i'lred, it is essential, for practical purposes, that the firing of the charges, as well as the order of ring, be controlled from the surface.

It is one object of this invention to provide an improved perforating device having explosive charges adapted to be controlled from the surface of the well bore so as to be fired in a predetermined, desired order.

An important object of the invention is to provide an improved device, of the character described, wherein a plurality of explosive charges are arranged to be iired by electrical means; the electrical circuit including means for controlling the iiow of current to each explosive charge, whereby an electrical current of predetermined intensity is required for each charge, thus making it possible to fire the charges in any predetermined order by varying the intensity of the transmitted electrical current.

Another object of the invention is to provide an improved device, of the character described, wherein a plurality of electrical resistances are connected in an electrical supply wire and are so arranged that as each charge is red, an additional resistance is interposed in the path of current ow, whereby each subsequent charge requires a current of increased intensity as compared to the current which fired the previous charge.

A particular object of the invention is to provide an improved device for firing explosive charges, wherein a plurality of electrical resistances of varying capacities are connected in the circuit, each resistance being associated with one of the explosive charges so as to control theintensity of the current necessary to lire that charge; the arrangement being such that each charge is red by a current of an intensity difierent from lthe current required to re the other charges, thus making it possible to readily control the order of firing of said charges.

Another object of the invention is to provide an improved device for electrically controlling the firing of a plurality of explosive charges in a predetermined order and having means for preventing the conductive mud in the well bore from.

grounding the circuit to create a short after one or more charges have been red, thereby obviating the danger of said mud interfering with the ring of the subsequent charges.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specication and by reference to the accompanying, drawing, in which an example of the invention is shown, and wherein:

Figure 1 is a view, partly insection and partly in elevation of a perforating device, constructed in accordance with the invention,

Figure 2 is a horizontal, cross-sectional view, taken on the line 2-2 of Figure 1,

Figure 3 is a wiring diagram of the improved control, and

Figure 4 is a wiring diagram of a modied form of control.

In the drawing, the numeral lll designates a substantially cylindrical body which houses a plurality of explosive charges C. Each charge is mounted in a diametrically extending opening il (Figure 2) in the body and includes a perforating bullet I2. A. powder chamber I3 is located behind the bullet and has the explosive powder therein, with a fusible wire lli extending therethrough. Electrical connection is made with the wire ill through a contact l5 which is engaged by a contact pin i6. The pin extends through an electrical insulating sleeve ll which is mounted in a plug i8 arranged to be threaded into one end of the opening ll to close the same. An electrical lead Wire i9, which is suitably insulated, has one end connected to the contact pin Aand extends upwardly through grooves and openings provided in the body. As will be explained, this wire conducts electrical current to the pin I6, contact l5 and wire I4, whereby said wire fires the explosive powder to expel or eject the bullet or projectile l2. Itis particularly pointed out that the construction of the body l0 and the explosive charges mounted therein form no part of the present invention and these parts are,

therefore, subject to variation. `So long as the charges C are adapted to be red by electrical current, the purposes of the invention may be accomplished.

, with one of the explosive charges CI.

An elongate sleeve or casing 2t has its lower end connected to the upper end of the body l by a coupling Za and a transversely extending connecting base or electrical receptacle 2| is disposed within the lower end of this sleeve, being preferably secured to the top of. the body lll. The base is constructed of electrical insulating material and hasa plurality of electrical sockets 22 therein. Each socket is connected to one of .the lead wires I9 extending from the explosive charges C, whereby a direct electrical connection is had between these parts.

For conducting electrical current to the sockets 22, an elongated plug 23-is insertable within the sleeve 29 and is provided with contact prongs 24, which depend therefrom and which are engageable within the sockets so as tol make electrical connection therewith. The number of prongs corresponds to the number of sockets. The plug 23 houses the control means for controlling the ring of the charges C and such means will be hereinafter explained. The plug is readily removable from the sleeve and has an axial contact in its top, said contact being adapted to be engaged by a spring-pressed plunger 26 which is mounted in a cap member 21. The cap member is threaded into the upper end of the sleeve 20, thereby closing the same and has the lower end of a cable or wire line 28 connected thereto. The cable is utilized for lowering the device `through the well casing A, or. through the well bore and is constructed of an electrical insulating material, whereby an electrical conductor or wire 29 may extend downwardly therethrough from the surface of the well. The lower end of. the conductor passes through an axial opening 2l' in the cap member and is connected with the plungcr 26. Manifestly, electrical current from the surface may flow downwardly from the surface through the conductor 29, plunger 26, contact 25, plug 23, prongs 24, sockets 22 and finally through'wires I9 to the explosive charges C to re the same.

For controlling the now of current to the various charges, the control means which is mounted in the plug 23 is provided and this means is clearly illustrated in the wiring diagram. Figure 3. The contact 25 which is located in the top of the plug is connected to the primary winding of a transformer 30 which is suitably mounted within the plug. A wire 3| leads from the transformer and a resistance RI is connected therein. Between the resistance and the transformer a lead wire 3|a is connected and the other end of this wire is connected to one of the prongs 24 of the plug. This plug has connection with one of the sockets 22, which, in turn, has connection With this arrangement, an electrical current which is conducted `through thewire 29 to the transformer passes through the transformer and then to the A wire 3|. Upon owing through the wire 3|, the

current passes through the wire 3|a, prong 24. socket v22, wire I9 and to the charge CI to fire the same. The resistance RI is of such size and that sufficient current cannot pass said resistance to' re any of the other -charges which are con- .nected to the wire 3| beyond said resistance, as

amarga wire 3l beyond the wire ib. wires 3io, Sid, Sie and 3H arefalso connected to the supply wire for conducting current to the other explosive charges C3, C4, C9 and C6 respectively; Between the wires 3|c and 3|d, a resistance R3 is connected in the -wire 3|, while a similar resistance R4 is located between wires 3|d and 3|e and a resistance R5 is disposed between wires 3| e and 3|f. Beyond the wire 3H, a resistance R6 is connected and the lower end of the supply wire 3| leads to one of the prongs 24 which engages one of the sockets 22. The socket to which the supply wire is connected leads to ground. All of the resistances RI to R6 are shown as of the same capacity and, therefore, set up the same electrical resistance to the flow of current. However, they could be of varying capacities.

In the operation of the device, a suitable variable transmitter T, or other device for transmitting a variable current, is mounted at lthe surface of the well bore and has connection with the upper end of the wire 29. This transmitter has been shown as a generator G associated with a variable resistance 32 having contact points therealong, whereby current of varying intensity may be transmitted. A suitable visible indicator, such as an ammeter M may be connected in the transmitting circuit. For the purposes of thisthe generator, through the transformer and then through wires 3|, 3|a and I9 to the first charge CI to nre the same. The transmitted current is of such intensity that sufficient current flows to this charge to :lire the same. However, the resistance R| is of such construction as to prevent sufllcient current to pass to the next charge C2 through the wire 3Ib and, therefore, before the next charge can be fired, the intensity of the current must be increased at the transmitter. This is done by moving the arm 32 to the next contact point 32h of the resistance 32. Such movement of said arm increases the intensity of the transmitted current to a point whereby sufcient current flows past the resistance R| to the wire 3|b `and thence to the charge C2. However, the resistance R2 blocks the current to the wire 3|c and the next charge C3. Thus, in order to fire this next charge C3, the current must be again increased in intensity to overcome the resistances RI and R2 connected in the supply wire 3|. Obviously, upon each increase of the intensity of the current the next successive charge is fired. The charges may be connected in any desired order and to any of the lead wires 3|a to f 3|f, whereby said charges may be fired in any arranging the connecting wires and resistances.

v'the intensity of the transmitted current is such It is pointed out lthat although six explosive charges have been shown and described, thisv number maybe varied as desired. I

The transformer 30 is connected in for the purpose of reducing the voltage, whereby the charges'may be fired by a relatively low voltage. By utilizing a low voltage for setting ofi the charges, interference of the conductive mud or fluid in the Well bore with the operation of the device is eliminated. It is manifest that when the rst charge is fired, the conductive mudv the circuit.

in the well bore may enter the opening l l in the body wherein the charge was mounted. This mud will, of course, contact the pin I 6 which is connected in the electrical circuit by the wire l 9. In effect, this mud sets up another resistance in the line and if a high voltage is employed for Y ring the charges, such resistance would be relatively low, as compared to the intensity of the current, with the result that the transmitted current for firing the subsequent charges would readily pass through the mud and the entire circuit grounded. Such an occurrence would prevent firing of the remaining charges.

The transformer T reduces the voltage and the charges are arranged to be fired by the relatively low voltage. Therefore, when the first charge is fired and the conductive mud enters the opening Il and engages the pin I6, the resistance created by the mud is `of a relatively high value, as compared to the voltage, with the re sult that the passage of current therethrough is defeated. This condition may also occur by the mud contacting the terminal connection between the wire I9 and pin i6. Thus, the current is directed through the supply wire 3l and the resistances therein, whereby the subsequent charges may be fired. In this manner, the entrance of eliminated, the current being conducted directly from the wire 29 to the wire 3l.

From the foregoing, it will be seen that a simple and eiective means for controlling the firing. of the explosive charges is provided. By arranging the resistances and the connections from the supply wire 3l to the charges, said charges may be fired in any desired order. The capacity of the resistances may be, of course, varied to permit a current ofany predetermined intensity to be utilized for firing the charges. The control is from the surface and may be manually actuated. The control mechanism is housed in the single plug 23, which may be readily removed for repair, or for any other reason, and it is manifest that by substituting a plug having resistances of different capacities and arranged in a different manner, for the plug 23, the order of ring may be changed.

In Figure 4, a slightly modified form of control mechanism is shown, wherein a plurality of resistances of varying capacities are employed in place of the resistances Rl to R6 which all have substantially the same capacity. In this form, a supply wire tl leads from the transformer and a wire Ma leads from the supply to the prong -2411 and socket 22 of the first explosive charge CI.

When current is directed over the wire Ma, the charge Cl is fired. The next charge C2 is connected to the supply wire 4l by a wire lib and this latter wire has a resistance 42h connected therein. The current which is utilized to re the first charge Cl is of insufficient intensity to pass the resistance 42h and, therefore, the first charge CI may be red without firing the second charge C2. The third charge C3 is connected to the supply through a wire Mc which has a resistance 2c connected therein. The resistance 42e is of a greater capacity than the resistance 62h, whereby a current of sufcient intensity to pass the resistance 62h and re the charge C2 is not suicient to pass the resistance 42e. Thus, the second charge may be lred without firing the third charge C3. Charges CG, C5 and C6 are also connected to the supply wire 4| by wires Md, le and dlf, respectively, and the wires Md, Me4 and lf have resistances 42d, 42e

and 42j connected therein. These resistances are of progressively increasing capacities and, with vsuch arrangement, it is manifest that a current of increased intensity must be employed for firing each subsequent charge. By properly arranging the resistances 42h to 62j, the charges may be red in any desired order. The operation of this form is substantially the same as the form shown in Figure 3, wherein a plurality of resistances of the same capacities are connected in the supply wire 3| between the wires leading to the charges. In Figure 3, as each charge is red, an additional resistance is, in effect, connected in the supply wire. Thus, in passing to the charge C2. the current need only flow through the one resistance RI, whereas in passing to the charge CS, the current must flow through the resistances RI to R5, whereby the intensity of the current must beprogressively increased to successively re the charges. In Figure 4, resistances of varying capacities are connected in the individual lead wires and the current must be progressively increased, in the same manner, to re the charges. In both forms, the control is from the surface and the charges may be exploded in any predetermined, desired manner.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials. as Well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A perforating device including, a body adaptJ ed to be lowered into a well bore, a plurality of explosive charges mounted in said body, means for conducting electrical current to the charges 45 to rire the same, and means in the electrical circuit remote from the charges for controlling the current Iflowing to each charge, whereby a current of a predetermined intensity is required to re each charge.

2. A perforating device including, a body adapted to be lowered into a well bore, a plurality of explosive charges mounted in said body, an electrical conductor extending from the surface for conducting electrical current to the charges, a plurality of resistances connected in the electrical circuit in advance of the explosive charges and associated therewith, whereby each charge is red by electrical current of a prede termined intensity. and means at the surface of the bore for transmitting electric currents of progressively increasing intensities through the circuit.

3. An apparatus for electrically firing a plurality of explosive charges including, an electrical circuit, and a series of electrical resistances forming part of said circuit and being separate from and associated with the explosive charges whereby the charges are successively red by electrical currents of different and progressively increasing intensities.

4. An apparatus for electrically firing a plurality of explosive charges including, an electrical circuit. a plurality of electrical resistances connected in the circuit, and means for automatically disposing an additional resistance in the current thereto.

path of the flowing current after each charge is fired, whereby each subsequent charge requires a current of increased intensity as corn-s pared to the previous charge.

5. An apparatus for electrically ring a plurality of explosive charges including, an electrical circuit, va plurality of electrical resistances connected in the circuit, means for automatically disposing an additional resistance in the path of the owing current after eachcharge is red, whereby each subsequent charge requires a current of increased intensity as compared to the previous charge, and means at the surface of the well bore for transmitting electric currents of varying intensities through the circuit to iire the charges.

6. An apparatus for electrically ilring at a distance a plurality of explosive charges including, means for successively ring the charges by transmitting electric currents of progressively increasing intensities to said charges, said means including a plurality of resistances connected in the circuit in advance of the charges and associated therewith so as to control the flow of 7. An apparatus for electrically firing a plurality of explosive charges includingan electrical circuit, and a series of electrical rsistances of varying capacities connected in the circuit remote from said charges, each resistance being associated with one of the charges so as to control the intensity of the current required to re said charge.

8. A perforating device including, a body I adapted to be lowered into a well bore, a plu rality of explosive charges mounted in said body, anelectrical conductor extending from the sur-1 face for conducting electrical current to the charges, control means removably mounted within the body and electrically connected in the con vductor in advance of the charges, said means being arranged to control the passage of current to the charges, whereby each charge may be fired by electrical current of a predetermined intensity. 9.l A perforating gun for boreholes comprising a gun body, bullets mounted for radial discharge from said gun body, a powder chamber arranged behind each bullet, a firing illament ln each of said powder chambers, and a ring circuit including a, source of power, a conductor connecting said source .of power to said lament, a resistance arranged in parallel with said filament, and a conductor connecting said source of power to the ground through said resistance.

10. A perforating gun for boreholes comprising a gun body, bullets mounted for radial discharge from said gun body, a powder chamber arranged behind each bullet, an electricalrlng means in each of said powder chambers, and a firing circuitl including a v source of power, a conductor connecting said source of power to said ilring means, a resistance arranged in parallel with said iring means, and a conductor connecting said source of power to the ground through said resistance.

LEONIDAS C. MILLER. 

